var arr1 = ['轻','轻','的','我','走','了'];

console.log(arr1.join('-'));

var arr2 = [['轻','轻','的'],['我','走','了']];

console.log(arr2.indexOf('了')); 

console.log(arr1.indexOf('了'));

var arr3 = ['正','如','我','轻','轻','的','来'];

console.log(arr3.indexOf('的')); 